import java.util.Scanner;

public class tesr3 {
    //洛谷 P5015 [NOIP2018 普及组] 标题统计
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        String str = scan.nextLine();
        int count = 0;
        for (int i = 0; i < str.length(); i++) {
            char c = str.charAt(i);
            if((c>=97&&c<=122) || (c>=65&&c<=106) || (c>=48&&c<=57)){
                count++;
            }
        }
        System.out.println(count);
    }
}
